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<head>
    <meta charset="UTF-8">
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    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
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<body>
    <script>
        var a = []
        for (let index = 0; index < 10; index++) {
            a[index] = function(){
                console.log(index);
            }
        }
        a[1]();//10
    </script>
</body>
</html>